Lock Miter Master Jig

When making boxes I use a number of joinery methods depending on the look that I want. The joinery most often ends up being part of the design and look that I am trying to accomplish. Dovetails give a certain character that says handcrafted, splines can be used in contrasting wood to give character also. But what do you do when building a box out of something like quarter sawn Zebra Wood that already has lots of character?

I have had a design that I have planned on making for a while using Zebra Wood. I plan on book matching the wood so that the lines match all the way around the box. The problem is that I don’t want to joinery to break up the lines so the corners need to be mitered together. Now I know there are many methods of doing this but the method that I decided to give a try is with a lock miter bit. Lock miters cut a profile into both pieces being mitered together giving more gluing surfaces and nice clean miters on the outside. The issue is that they have a reputation of being a pain to set up with lots of trial and error adjustments of the bit high and placement of the router table fence.

After finally deciding the lock miter bit was still the method that I wanted to go with I purchased the bit but put off using it for a couple of reasons all to do with adjustments. The first I took care of by adding a Kreg Precision Router Insert Plate that I could mount my Triton router to, instead of the older Makita router that I have used for years and is tough to adjust to fine increments.

So that just left me with how to adjust the lock miter bit without a couple of dozen adjustments in all directions. After talking with David Venditto of Infinity Tools on the MWA Podcast he mentioned that they had a new Lock Miter Master Gauge that would help with setup….and to be honest I was not sure this would be the cure all but decided to give it a try. So a few weeks ago I finally took the bit out installed it in the router table and gave it a shot. The gauge is installed using the rare earth magnets to hold it onto the router bit cutter. Slide it up as far as it will go and it is ready for you to adjust.

The first set up was an almost perfect alignment! I was amazed at how simple it was, so I decided that I would record the second for anyone interested. Rather than go through all of the details here take a look at the video below. Note that I recorded straight through and only cut a few parts but didn’t breakaway for the setup.

A last couple of notes: I published the video before releasing this post and have had several e-mail asking if the Lock Miter Master Jigs can be used with lock miter bits from manufactures other than Infinity. So I asked the guys over at Infinity and the official answer is….maybe. They have tested the jig on most of the major competitors and it worked fine on all of them but there are a ton of manufactures that make lock miter bits so it’s impossible to say 100% that it will work. One other recommendation that I did not do in the video is to use a feather boards to help secure the work pieces. This will help keep the stock steady against the fence to make a better joint as well as being safer than not using them.